[403] THE ALG^ 167 



Docidium minutum Ralfs. 



PleurotcE7tiuin ? minutum (Ralfs.) Delponte. 

 In freshwater near Prince William Sound. 

 Diameter 1 1 At, length 135 /x. 



Arthrodesmus convergens Ehrenb. (Plate xliv, fig. 14.) 



In a freshwater pond near Seldovia, Cook Inlet (422). Rare. 

 Diameter 32 /x, length 32 // without the spines. 



Xanthidium antilopaeum (Breb.) Kuetz. (Plate xliii, fig. 38.) 



In a freshwater pond near Cook Inlet. 



Diameter 55 At, length 55 /z including the spines. The spines near 

 the apex of the semi-cells are more nearly straight than in the figures 

 given of this species. 



Xanthidium armatum (Breb.) Ralfs. (Plate xliv, fig. 18.) 



In a freshwater pond near Virgin Bay, Prince William Sound. 

 Diameter 81//, length 128//. Most of the spines are bifurcated, 



with the points divergent. 



Cosmarium granatum Brdb. (Plate xliii, fig. 8.) 

 In a freshwater pond near Seldovia, Cook Inlet. 

 Diameter i8/«, length 32 /z. 



Cosmarium constrictum Delp. (Plate xliii, figs. 33, 34.) 



In a freshwater pool near Virgin Bay, Prince William Sound (300) , 

 Diameter 40 /x, length 65 /x. 



Cosmarium bioculatum Br^b. (Plate xliii, fig. 28.) 



Common in a freshwater pond, Seldovia, Cook Inlet (422). 

 Diameter 16-18//, length 17-18 /z. 



Cosmarium hammeri Reinsch. (Plate xliii, fig. 7.) 

 In a freshwater pond near Seldovia, Cook Inlet (422). 

 Diameter 10-14 /z, length 18-22/^. Very close to the variety 5a<5flr/z- 



gustatum of Boldt. The angles are a little more acute than in the 



type ; the apex of the semicells is very emarginate. 



Cosmarium depressum (Naeg.) Lund. (Plate xliii, fig. 17.) 

 In a freshwater pond near Seldovia, Cook Inlet. 

 Diameter 16-20//, length i8/z. 



Cosmarium holmiense Lund. (Plate xliv, fig. 28.) 

 In freshwater near Kukak Bay. 

 Diameter 32/1, length 54;/. 



Cosmarium venustum (Br^b.) Arch. 



In a freshwater pond near Seldovia, Cook Inlet. 



